Air quality sensor/interruptor

ABSTRACT

An air quality sensor and interrupter system includes an air quality sensor to measure the air quality around a gas appliance and an appliance shut-off device to turn off the gas appliance in response to a signal from the sensor indicating unsafe air. An exhaust can also be activated to remove the unsafe air. Unsafe air can be indicated by a measurement of 18.5% or less oxygen in the air. If the sensor fails, an alarm can alert the user and the appliance shut off until the sensor is replaced or repaired. A bypass allows the user to keep the appliance turned on, but only for a limited amount of time. The user can keep utilizing the bypass to keep the appliance turned on for extended periods of time.

CROSS REFERENCE TO RELATED APPLICATIONS

The present invention is a continuation-in-part application of U.S. patent application Ser. No. 11/404,313, filed Apr. 14, 2006, which claims priority to U.S. Provisional Application Serial No. 60/671,952, filed Apr. 15, 2005.

BACKGROUND

1. Field of Invention

The present invention relates generally to air quality detection systems, and in particular, to such systems that take action based on the air quality detected.

2. Related Art

Gas appliances can generate unsafe levels of various gases, such as carbon monoxide (CO), into the air. Such gases need to be detected so that people within the air space do not get ill or suffer any other health-related problems. For example if a burner system in a gas appliance is not burning properly, unsafe levels of combustion by-products are released into the environment because of incomplete combustion.

One type of gas detection system uses the oxygen detection safety-pilot (ODS) technology on gas appliances. A typical ODS pilot system includes an oxygen-sensitive pilot burner that regulates flame characteristics, a thermocouple positioned in the mantle of the pilot flame, and a safety shut-off valve. The pilot flame is designed to be stable within a very narrow operating range. The thermocouple responds to changes in the pilot flame characteristics and, when heated, generates a voltage, e.g., in the millivolt range, which keeps the gas supply valve in the open position.

However, if low levels of oxygen are detected by the ODS system, the flame extinguishes. The loss of flame causes the thermocouple to cool. This cooling reduces the voltage, which causes the gas valve to return to its normally closed position, thus turning off the fuel supply to the appliance. The unit will not operate until the space is properly ventilated and adequate oxygen is introduced, and the appliance is restarted.

Although relatively effective, there are several inherent problems with ODS systems. These include, but are not limited, to susceptibility to drafts, pilot positioning, gas supply, orifice sizing, and heating value of the gas. Due to the nature of the ODS pilot system, it is subject to nuisance shutdowns from overheating conditions on the thermocouple cold junction.

Non-pilot light based systems, such as described in U.S. Pat. No. 4,482,311, address some of the deficiencies of ODS pilot systems. However, the system of the '311 patent and known systems for automatic shut-off of a heating system based on carbon monoxide detection, such as described in U.S. Pat. No. 5,793,296, do not go much beyond shutting off the system. With these systems, when a sensor/detector fails, the system is no longer functional. In addition, when low oxygen is detected, the system simply shuts off the heating system. However, dangerous amounts of low oxygen may still be present.

Therefore, there is a need for an air quality detection system that overcomes the disadvantages of conventional systems discussed above.

SUMMARY

According to one aspect of the invention, an air quality sensor/interrupter includes an air quality sensor and a means of interrupting the operation of the appliance when a low air quality is detected. In one embodiment, when the oxygen level is approximately 18.0% or lower, a signal is sent to the shut-down mechanism to shut down the gas appliance.

The air quality sensor/interrupter is a device that measures air quality in a confined space, and if unsafe air is detected, shuts down the appliance(s) affecting the air in the monitored space. The sensor may communicate to the interrupter or shut-down mechanism by a wired or a wireless system. Upon receipt of the signal, the interrupter will stop the flow of power, gas, or electricity to the heating element of the appliance(s). In one embodiment, the interrupter may shut down only the heater or burner element of the system and allow the rest of the appliance to function, such as blowers and lights. The appliance is not turned back on until the interrupter or system is reset, either by the user or automatically upon detection of “safe” air.

Thus, because the air quality sensor/interrupter measures the actual air quality in the space and shuts down the appliance based on a detection of unsafe air, the present invention does not have many of the inherence problems of conventional ODS systems.

When unsafe air is detected, the system also activates an exhaust to clear away the unsafe air. The exhaust may be a fan or any conventional exhaust device. Once the system is reset, either with a “safe” air detection or by the user, the exhaust is turned off. This ensures the space proximate the sensor does not retain unsafe air, which is especially desirable in areas with human or animal contact.

In another embodiment, if the sensor/interrupter fails, the gas supply to appliances connected to the system will be shut off and an alarm will be activated to let the user know of the faulty device. Once a new and operational device is installed, the system opens up the gas supply, assuming the air quality is safe. However, if a new device is not readily available, the system may be equipped with a user-enabled bypass switch, which allows gas to flow to the appliances for operation. In one embodiment, when the bypass switch is enabled, the switch is only operational for a set period of time, such as 36 hours. After 36 hours, the gas supply is shut off again to the appliances, although the user may again trigger the bypass switch. Such a mechanism enables the appliances to operate even without a functional sensor/interruptor, but does not allow continuous operation unless a functional sensor/interruptor is installed.

Thus, features of the present invention provide a safer detection and shut-off system, as unsafe air is automatically removed upon an unsafe air detection and the user is warned when the detection mechanism fails, while still allowing the connected appliances to operate.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram of an air quality detection/shut-down system according to one embodiment;

FIG. 2 is a flow chart showing steps for shutting down an appliance when unsafe air is detected according to one embodiment;

FIG. 3 is a block diagram of an air quality detection/shut-down system with an automated exhaust system according to one embodiment;

FIG. 4 is a block diagram of an air quality detection/shut-down system with a faulty detector warning system according to one embodiment; and

FIG. 5 is a flow chart showing steps for removing unsafe air when unsafe air is detected and/or warning the user of a faulty detection mechanism.

Embodiments of the present invention and their advantages are best understood by referring to the detailed description that follows.

DETAILED DESCRIPTION

According to one embodiment of the present invention, a sensor is used to measure the quality of air in a room or area. If the measurement indicates unsafe air, a signal is sent to a shut-down device, which then shuts down the appliance or appliances in the monitored air space.

The sensor may employ one of several known technologies and products, such as electromechanical, semiconductor, catalytic bead, and zirconia lambda. Suitable sensors or detectors include the TX-2000 Toxic Gas and OX-2000 Oxygen Intrinsically Safe series of detectors from Enmet Corporation of Ann Arbor, Mich. These detectors are capable of continually monitoring toxic gases or oxygen and indicating when a certain gas is detected or a certain gas has reached a threshold, such as by an audio alarm or visual display. Gases that can be monitored include, but may not be limited to chlorine (Cl₂), carbon monoxide (CO), hydrogen (H₂), hydrogen sulfide (H₂S), ammonia (NH₃), nitrogen oxide (NO), nitrogen dioxide (NO₂), oxygen (O₂), and ozone (O₃).

In one embodiment, when the sensor detects low oxygen levels, such as at 18.0% or less, an alarm will sound and a signal will be sent to a shut-down device or interrupter. The signal can be sent along a wired channel, such as along a wire, or through a wireless communication. An example of a wireless shut-down device is a RR-1 or RR-1A remote system receiver and transmitter from the Robert H. Peterson Company, the City of Industry, Calif. The RR-1 or RR-1A system can be modified to act as transmitter and receiver grounding device.

Thus, once a signal is received indicating that the quality of the air has dropped below an acceptable level, the grounding circuit will activate or close and either directly ground the thermocouple/thermopile/battery or magnet power circuit. This would then result in the magnet/valve dropping out or shutting off, causing the gas appliance to shut down. Alternatively, a remote transmitter may be activated to send a signal to a grounding system which would shut down the gas appliance.

FIG. 1 is a block diagram showing one embodiment of the just-described invention. In FIG. 1, an air quality sensor and control system 100 is shown in use with a gas appliance 102. Gas appliance 102 is shown as a gas log system, although any suitable gas appliance can be used with the present invention. Gas appliance 102 is connected to a receiver 104, which operates to receive signals and in response to the signals, turn gas appliance 102 off or on. Receiver 104 receives signals transmitted by a transmitter 106. Signals can be transmitted wireless or over a wired connection. Receiver 104 and transmitter 106 are conventional components to a system, such as the Model # RR-1 or RR-1A kit from the RH Peterson Co. of the City of Industry. An oxygen sensor 108 is connected to transmitter 106. The sensor may be located in the whole house or room area dependent on the sensitivity of the detector. Multiple detectors may be required in a whole house situation.

When oxygen sensor 108 detects low oxygen, e.g., 18.0% or lower, or a toxic gas, it sends a signal to transmitter 106. In response, transmitter 106 sends a turn-off signal to receiver 104. Receiver 104 then turns off gas appliance 102, such as by closing a hot lead/ground circuit 110 in gas appliance 102. In one embodiment, only the burner or gas supply is shut down, while leaving other components of the appliance functional. In other embodiments, all functions or components of the appliance are shut down upon receiving indication of low oxygen environment or toxic air quality.

FIG. 2 is a flowchart illustrating steps for shutting down a gas appliance, according to one embodiment of the present invention. In step 200, the quality of the air proximate to the gas appliance is sensed or measured. Sensing can be with any conventional air quality sensor to detect oxygen levels in the air or to detect the presence of toxic gas. In step 202, a determination is made whether the air quality is safe. In one embodiment, unsafe air quality occurs when the oxygen level is approximately 18.0% or lower. If an unsafe air quality is detected, as determined in step 202, a signal is sent, in step 204, to a device or system for turning off the gas appliance. The device or system may comprise of a transmitter/receiver pair or a single transceiver. If the air quality is not classified as unsafe, then no signal is sent and the gas appliance continues its normal operation in step 206. In step 208, upon receipt of a signal indicating unsafe air quality, the gas appliance is shut down or turned off, either in whole or only specific parts, such as the gas burners. The gas appliance remains shut down until the quality of air is no longer unsafe.

As a result, the gas appliance does not continue generating fire or producing unsafe air, such as with an excess of carbon monoxide, when unsafe air is detected without being dependent on the pilot light. Consequently, reliance on the pilot light is eliminated, thereby eliminating disadvantages of conventional systems using the pilot light.

FIG. 3 is a block diagram of an air quality detection/shut-down system 300 with an automated exhaust system according to one embodiment. System 300 is the same as system 100 described above, but includes an exhaust system 302 in communication with receiver 104. Note that in other embodiments, exhaust system can be in communication directly with transmitter 106. When oxygen sensor 108 detects unsafe air, receiver 104 turns off the gas supply to gas appliance 102, as described above. With this embodiment, when oxygen sensor 108 detects unsafe air, exhaust system 302 also receives a signal, either through transmitter 106 or receiver 104. In response, exhaust system 302 removes the unsafe air surrounding sensor 108 and/or appliance 102. As a result, the corresponding surrounding area is made safe to humans, animals, or anything in contact with the area.

The exhaust system can be any conventional exhaust, including vacuum systems that suck in and/or filter the air and fan systems that blow out the unsafe air. The exhaust systems may be activated upon immediate receipt of the unsafe air detection signal and may operate simultaneously with the appliance shut off system. However, simultaneous operation is not required. Furthermore, multiple exhaust systems or devices may be utilized, depending in part on various factors, including the number of sensors 108, the size of the affected area, the efficiency of the exhaust systems, and the urgency or time requirements for removing the unsafe air upon an unsafe air detection. After the unsafe air is removed, system 300 resets itself. System reset can be triggered in any number of ways, including when sensor 108 detects safe air again, the user manually resetting the system, or after the exhaust system has been operating for a specified period of time.

FIG. 4 is a block diagram of an air quality detection/shut-down system 400, in which an alarm system 402 and a bypass system 404 are in communication with sensor 108. In system 400, when sensor 108 fails or otherwise becomes inoperative, such as accuracy falls below a set threshold, alarm system 402 notifies the user. Notification can be provided using various methods, including an audio alarm, a visual alarm, a combination of the two, and an automated message sent to a user's cell phone or computer. This gives the user instant notification for sensor failure, which minimizes the time required to fix or install a new sensor 108. As a result, the time that system 400 is not functioning properly can be greatly reduced. Note that when alarm system 402 is triggered, a signal is sent to transmitter 106 and/or receiver 104 to shut down gas to appliance 102 and any other connected appliances. These appliances remain shut down until sensor 108 is replaced or repaired.

There may be situations where the faulty sensor cannot be readily fixed or replaced, but that appliances connected to system 400 still need to be operable. In this situation, bypass system 404 enables the user to manually bypass appliance shut down and start or maintain the flow of gas to appliance 102. In one embodiment, the bypass is only in effect for a specified period of time, such as 36 hours. Other periods of time may be set by the user, depending on system needs and uses. The user may continually restart the bypass system, but must do so no later than the specified period of time. This allows the system to continue functioning, but also requires the user to monitor the system as well. Consequently, a level of safety is maintained due to the necessity for user intervention. When sensor 108 is repaired or replaced, system 400 begins normal operation again. Note that alarm system 402 and/or bypass system 404 may be used in conjunction with exhaust system 302.

FIG. 5 is a flow chart 500 illustrating steps for operating the systems of FIG. 3 and 4 according to one embodiment. In step 502, a determination is made as to whether the air sensor is faulty. Faulty can mean that the sensor has failed or that its accuracy has dropped below a minimum threshold. If the air sensor is functioning properly, the air quality is sensed at step 200. Steps 200 to 208 are the same as in FIG. 2 and thus their description will not be repeated. However, if as determined in step 502 that the air sensor is faulty, a turn off signal is sent (step 204) and the appliance is turned off (step 208). Next, or simultaneously, an alarm is activated in step 504. Alarm activation may include a visual alarm, an audio alarm, a combination of the two, and/or a call sent to the user, such as via a cell phone or computer.

In step 506, the user determines whether the appliances are to remain operational. If not, appliances remain shut off until a functional sensor is in place. However, if the appliances are to remain operational, a bypass is activated to resume or maintain gas flow to the appliance in step 508. Step 510 determines whether the appliances have been operational more than a specified period of time after the bypass was activated. If so, the appliances are turned off at step 208. However, if the specified period of time has not passed, the user may activate the bypass again in step 508 to continue operation of the appliances. Once the air sensor has been repaired or replaced, normal operation resumes at step 200 with air quality sensing or detection.

So, the above enables the air sensor to be continually monitored for proper operation and for the appliances to be turned off in the event of air sensor failure. However, the appliances can remain operational by a user bypass, although the bypass is only for a specified period of time, which can be continually reset by the user for uninterrupted operation.

In step 512, after unsafe air is detected, an exhaust system is activated, which can be in response to the turn-off signal in step 204, to a separate signal from sensor 108, or to the appliance being turned off. The exhaust system is deactivated when the air quality is detected to be safe or when the user deactivates the system. Note that step 512 can be performed in parallel with or before step 208 and does not need to sequentially follow step 208. The exhaust system may remain activated until safe air is detected or when the user manually turns off the exhaust system.

The above features provide a system that is safer than conventional systems, while still allowing the user the flexibility to maintain operation of the appliances if desired.

Having thus described embodiments of the present invention, persons skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the invention. 

1. An air quality sensor and interrupting system, comprising: an air quality sensor configured to measure the quality of air proximate to a gas appliance and generate a signal when unsafe air is detected; a gas shut off device configured to turn off at least one portion of the gas appliance in response to the signal sent from the air quality sensor; and an exhaust configured to remove the unsafe air when unsafe air is detected.
 2. The system of claim 1, wherein the exhaust is a vacuum device.
 3. The system of claim 1, wherein the exhaust is a blowing device.
 4. The system of claim 1, further comprising a bypass configured to allow a user to keep the gas appliance turned on if the air quality sensor fails.
 5. The system of claim 4, wherein the bypass only allows the gas appliance to be turned on for a set period of time without additional user input.
 6. The system of claim 1, further comprising an alarm to notify the user when the air quality sensor fails.
 7. The system of claim 6, wherein the alarm is an audio alarm, a visual alarm, or an audio and visual alarm.
 8. An air quality sensor and interrupting system, comprising: an air quality sensor configured to measure the quality of air proximate to a gas appliance and generate a signal when unsafe air is detected; a gas shut off device configured to turn off at least one portion of the gas appliance in response to the signal sent from the air quality sensor; and an alarm coupled to the sensor, wherein the alarm notifies a user when the sensor fails.
 9. The system of claim 8, further comprising a bypass configured to allow the user to keep the gas appliance turned on if the air quality sensor fails.
 10. The system of claim 9, wherein the bypass only allows the gas appliance to be turned on for a set period of time without additional user input.
 11. An air quality sensor and interrupting system, comprising: an air quality sensor configured to measure the quality of air proximate to a gas appliance and generate a signal when unsafe air is detected; a gas shut off device configured to turn off at least one portion of the gas appliance in response to the signal sent from the air quality sensor; and a bypass configured to allow a user to keep the gas appliance turned on if the air quality sensor fails.
 12. The system of claim 11, wherein the bypass only allows the gas appliance to be turned on for a set period of time without additional user input.
 13. A method for operating a gas appliance, comprising: sensing an air quality of air proximate to the gas appliance; determining whether the air quality is unsafe; turning off at least a portion of the gas appliance if the air quality is unsafe; and removing the unsafe air.
 14. The method of claim 13, wherein the removing comprises vacuuming.
 15. The method of claim 13, wherein the removing comprises blowing.
 16. The method of claim 13, further comprising notifying a user when the sensing fails.
 17. The method of claim 16, wherein the notifying is with an audio alarm, a visual alarm, or an audio and visual alarm.
 18. A method for operating a gas appliance, comprising: sensing an air quality of air proximate to the gas appliance; determining whether the air quality is unsafe; turning off at least a portion of the gas appliance if the air quality is unsafe; notifying a user if the sensing fails; and turning off at least a portion of the gas appliance if the sensing fails.
 19. The method of claim 18, further comprising allowing the user to bypass turning off the gas appliance when the sensing fails to keep the appliance turned on.
 20. The method of claim 19, wherein the appliance is turned on only for a limited amount of time when the bypass is used.
 21. The method of claim 18, further comprising removing unsafe air when the air quality is determined unsafe. 